Sean,
Why would you want to ditch Carnoustie from the rota?
A fairly charmless place to be sure, but it has some absolutely fantastic holes, especially 2,3,5,6,10,14,15 and 17.
Much better than Troon, surely, which only has a back nine to recommend it...
And much, much better than Birkdale, which has 12, 15 and... not much else of interest.